Maarten Schmidt via Caltech.
Today in science: On February 5, 1963, Dutch astronomer and Caltech professor Maarten Schmidt had a moment of eureka while studying quasi-stellar radio source, or quasar, which had profound implications for the way scientists would view the universe. Schmidt studied a quasar known as 3C273 that looked like a star with the addition of a mysterious jet. But even stranger was his spectrum. Astronomers examine the spectrum, or range of light wavelengths, emitted by a star to decipher the composition of the object. But the emission lines of the 3C273 spectrum does not match any known chemical element. Schmidt suddenly realized that 3C273 contained the very normal element hydrogen. It was simply difficult to identify because the spectral lines of hydrogen did not appear where expected; instead, they shifted far toward the red end of the spectrum. There could be such a large redshift if the 3C273 was so far away, about 3 billion light-years away.
Dr. Schmidt recalled the excitement of his revelation to EarthSky. He said:
This understanding came immediately: my wife still remembers that she was spending up and down much of the night.
The implications were these: for the quasar to be so far away and still visible, the 3C273 must be intrinsically very bright and very powerful. It is now believed to shine with the light of two trillion stars like our sun. It is hundreds of times the light of our entire Milky Way galaxy. However, the 3C273 appears to be less than a light-year apart, in contrast to the 100,000 light-years of our Milky Way.
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Quasar 3C273 is not only distant. It is also extremely bright, involving powerful processes of unknown energy production in 1963. Schmidt announced his revelation about quasars in the magazine Nature on March 16, 1963.
Maarten Schmidt is a Dutch astronomer who, in 1963, recognized that quasars are in the very distant universe and must therefore be extremely powerful sources of energy.
X-ray image of 3C273 and its ray. Today, this quasar is known to be at the center of a giant elliptical galaxy. Image via Chandra X-ray Observatory.
Hundreds of thousands of quasars are known today and many are more distant and more powerful than the 3C273. It is no exaggeration to say that they turned the science of astronomy into their ear. Why, for example, are these powerful quasars so far away in space? Light travels at a finite speed (186,000 miles per second) and we only see quasars in a distant space and therefore in a distant past. These strange objects only existed in the primitive universe and no longer exist in the current universe. Because?
In the 1960s, 3C273 and other similar quasars were strong evidence against Fred Hoyle’s steady-state theory, which suggested that matter is continuously created as the universe expands, resulting in a universe that is the same everywhere. Quasars showed that the universe was not the same everywhere and therefore helped initiate the cosmology of the Big Bang.
But steady-state theory had been losing ground even before 1963. The biggest change caused by Maarten Schmidt’s revelation about the 3C273 quasar was in our way of think about our universe.
In other words, the idea that the 3C273 was extremely bright and yet took up so little space suggested powerful energies that astronomers had not contemplated before. 3C273 gave astronomers one of the first clues we live in in a universe of colossal explosive events – and extreme temperatures and luminosities – a place where mysterious black holes abound and play an important role.
According to a March 2013 email from Caltech:
In 1963, Schmidt’s discovery gave us an unprecedented look at how the universe behaved at a much younger period in its history, billions of years before the birth of the sun and its planets. Later, Schmidt, along with his companion Donald Lynden-Bell, discovered that quasars are galaxies that harbor supermassive black holes billions of light-years away, not stars in our own galaxy, as previously thought. . His overarching work drastically increased the scale of the observable universe and advanced our current view of the violent nature of the universe in which massive black holes play a dominant role.
What are quasars? Today astronomers believe that a quasar is a compact region at the center of a galaxy in the primitive universe. The compact region is believed to surround a central supermassive black hole, like the black hole believed to reside in the center of our own Milky Way galaxy and many (or most) other galaxies. The powerful luminosity of a quasar is believed to be the result of processes taking place in one accretion disk, or disk of material surrounding the black hole, as these supermassive black holes consume stars that pass too close. Such activities occur during the merging of galaxies, which reached their peak in the early universe.
ULAS J1120 + 0641 was the farthest known quasar in 2011. The quasar appears as a faint red dot near the center. Composite image created from Sloan Digital Sky Survey and UKIRT Infrared Deep Sky Survey, via Wikimedia Commons.
Chinese-born American astrophysicist Hong-Yee Chiu coined the name quasar in May 1964 in the publication Physics today. He wrote:
Until now, the clumsy name “quasi-stellar radio sources” was used to describe these objects. Because the nature of these objects is completely unknown, it is difficult to prepare a short, appropriate nomenclature for them so that their essential properties are evident from their name. For convenience, the abbreviated form “quasar” will be used throughout this document.
Currently, the farthest known quasar is ULAS J1342 + 0928, but it could be dethroned at any time. It has a redshift of z = 7.54 and existed when the universe was about 690 million years old, only 5% of its current age.
Summary: Today in science, on February 5, 1963, Maarten Schmidt unraveled the mystery of quasars and pushed back the edges of our cosmos. His view of the most distant and distant known objects has changed the way scientists view the universe.
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